[thirdparty/hostap.git] / wpa_supplicant / bgscan_learn.c

/*
 * WPA Supplicant - background scan and roaming module: learn
 * Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "eloop.h"
#include "list.h"
#include "common/ieee802_11_defs.h"
#include "drivers/driver.h"
#include "config_ssid.h"
#include "wpa_supplicant_i.h"
#include "driver_i.h"
#include "scan.h"
#include "bgscan.h"

struct bgscan_learn_bss {
	struct dl_list list;
	u8 bssid[ETH_ALEN];
	int freq;
	u8 *neigh; /* num_neigh * ETH_ALEN buffer */
	size_t num_neigh;
};

struct bgscan_learn_data {
	struct wpa_supplicant *wpa_s;
	const struct wpa_ssid *ssid;
	int scan_interval;
	int signal_threshold;
	int short_interval; /* use if signal < threshold */
	int long_interval; /* use if signal > threshold */
	struct os_reltime last_bgscan;
	char *fname;
	struct dl_list bss;
	int *supp_freqs;
	int probe_idx;
};


static void bss_free(struct bgscan_learn_bss *bss)
{
	os_free(bss->neigh);
	os_free(bss);
}


static int bssid_in_array(u8 *array, size_t array_len, const u8 *bssid)
{
	size_t i;

	if (array == NULL || array_len == 0)
		return 0;

	for (i = 0; i < array_len; i++) {
		if (os_memcmp(array + i * ETH_ALEN, bssid, ETH_ALEN) == 0)
			return 1;
	}

	return 0;
}


static void bgscan_learn_add_neighbor(struct bgscan_learn_bss *bss,
				      const u8 *bssid)
{
	u8 *n;

	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
		return;
	if (bssid_in_array(bss->neigh, bss->num_neigh, bssid))
		return;

	n = os_realloc_array(bss->neigh, bss->num_neigh + 1, ETH_ALEN);
	if (n == NULL)
		return;

	os_memcpy(n + bss->num_neigh * ETH_ALEN, bssid, ETH_ALEN);
	bss->neigh = n;
	bss->num_neigh++;
}


static struct bgscan_learn_bss * bgscan_learn_get_bss(
	struct bgscan_learn_data *data, const u8 *bssid)
{
	struct bgscan_learn_bss *bss;

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
		if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
			return bss;
	}
	return NULL;
}


static int bgscan_learn_load(struct bgscan_learn_data *data)
{
	FILE *f;
	char buf[128];
	struct bgscan_learn_bss *bss;

	if (data->fname == NULL)
		return 0;

	f = fopen(data->fname, "r");
	if (f == NULL)
		return 0;

	wpa_printf(MSG_DEBUG, "bgscan learn: Loading data from %s",
		   data->fname);

	if (fgets(buf, sizeof(buf), f) == NULL ||
	    os_strncmp(buf, "wpa_supplicant-bgscan-learn\n", 28) != 0) {
		wpa_printf(MSG_INFO, "bgscan learn: Invalid data file %s",
			   data->fname);
		fclose(f);
		return -1;
	}

	while (fgets(buf, sizeof(buf), f)) {
		if (os_strncmp(buf, "BSS ", 4) == 0) {
			bss = os_zalloc(sizeof(*bss));
			if (!bss)
				continue;
			if (hwaddr_aton(buf + 4, bss->bssid) < 0) {
				bss_free(bss);
				continue;
			}
			bss->freq = atoi(buf + 4 + 18);
			dl_list_add(&data->bss, &bss->list);
			wpa_printf(MSG_DEBUG, "bgscan learn: Loaded BSS "
				   "entry: " MACSTR " freq=%d",
				   MAC2STR(bss->bssid), bss->freq);
		}

		if (os_strncmp(buf, "NEIGHBOR ", 9) == 0) {
			u8 addr[ETH_ALEN];

			if (hwaddr_aton(buf + 9, addr) < 0)
				continue;
			bss = bgscan_learn_get_bss(data, addr);
			if (bss == NULL)
				continue;
			if (hwaddr_aton(buf + 9 + 18, addr) < 0)
				continue;

			bgscan_learn_add_neighbor(bss, addr);
		}
	}

	fclose(f);
	return 0;
}


static void bgscan_learn_save(struct bgscan_learn_data *data)
{
	FILE *f;
	struct bgscan_learn_bss *bss;

	if (data->fname == NULL)
		return;

	wpa_printf(MSG_DEBUG, "bgscan learn: Saving data to %s",
		   data->fname);

	f = fopen(data->fname, "w");
	if (f == NULL)
		return;
	fprintf(f, "wpa_supplicant-bgscan-learn\n");

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
		fprintf(f, "BSS " MACSTR " %d\n",
			MAC2STR(bss->bssid), bss->freq);
	}

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
		size_t i;
		for (i = 0; i < bss->num_neigh; i++) {
			fprintf(f, "NEIGHBOR " MACSTR " " MACSTR "\n",
				MAC2STR(bss->bssid),
				MAC2STR(bss->neigh + i * ETH_ALEN));
		}
	}

	fclose(f);
}


static int in_array(int *array, int val)
{
	int i;

	if (array == NULL)
		return 0;

	for (i = 0; array[i]; i++) {
		if (array[i] == val)
			return 1;
	}

	return 0;
}


static int * bgscan_learn_get_freqs(struct bgscan_learn_data *data,
				    size_t *count)
{
	struct bgscan_learn_bss *bss;
	int *freqs = NULL, *n;

	*count = 0;

	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
		if (in_array(freqs, bss->freq))
			continue;
		n = os_realloc_array(freqs, *count + 2, sizeof(int));
		if (n == NULL)
			return freqs;
		freqs = n;
		freqs[*count] = bss->freq;
		(*count)++;
		freqs[*count] = 0;
	}

	return freqs;
}


static int * bgscan_learn_get_probe_freq(struct bgscan_learn_data *data,
					 int *freqs, size_t count)
{
	int idx, *n;

	if (data->supp_freqs == NULL)
		return freqs;

	idx = data->probe_idx;
	do {
		if (!in_array(freqs, data->supp_freqs[idx])) {
			wpa_printf(MSG_DEBUG, "bgscan learn: Probe new freq "
				   "%u", data->supp_freqs[idx]);
			data->probe_idx = idx + 1;
			if (data->supp_freqs[data->probe_idx] == 0)
				data->probe_idx = 0;
			n = os_realloc_array(freqs, count + 2, sizeof(int));
			if (n == NULL)
				return freqs;
			freqs = n;
			freqs[count] = data->supp_freqs[idx];
			count++;
			freqs[count] = 0;
			break;
		}

		idx++;
		if (data->supp_freqs[idx] == 0)
			idx = 0;
	} while (idx != data->probe_idx);

	return freqs;
}


static void bgscan_learn_timeout(void *eloop_ctx, void *timeout_ctx)
{
	struct bgscan_learn_data *data = eloop_ctx;
	struct wpa_supplicant *wpa_s = data->wpa_s;
	struct wpa_driver_scan_params params;
	int *freqs = NULL;
	size_t count, i;
	char msg[100], *pos;

	os_memset(&params, 0, sizeof(params));
	params.num_ssids = 1;
	params.ssids[0].ssid = data->ssid->ssid;
	params.ssids[0].ssid_len = data->ssid->ssid_len;
	if (data->ssid->scan_freq)
		params.freqs = data->ssid->scan_freq;
	else {
		freqs = bgscan_learn_get_freqs(data, &count);
		wpa_printf(MSG_DEBUG, "bgscan learn: BSSes in this ESS have "
			   "been seen on %u channels", (unsigned int) count);
		freqs = bgscan_learn_get_probe_freq(data, freqs, count);

		msg[0] = '\0';
		pos = msg;
		for (i = 0; freqs && freqs[i]; i++) {
			int ret;
			ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d",
					  freqs[i]);
			if (os_snprintf_error(msg + sizeof(msg) - pos, ret))
				break;
			pos += ret;
		}
		pos[0] = '\0';
		wpa_printf(MSG_DEBUG, "bgscan learn: Scanning frequencies:%s",
			   msg);
		params.freqs = freqs;
	}

	wpa_printf(MSG_DEBUG, "bgscan learn: Request a background scan");
	if (wpa_supplicant_trigger_scan(wpa_s, &params)) {
		wpa_printf(MSG_DEBUG, "bgscan learn: Failed to trigger scan");
		eloop_register_timeout(data->scan_interval, 0,
				       bgscan_learn_timeout, data, NULL);
	} else
		os_get_reltime(&data->last_bgscan);
	os_free(freqs);
}


static int bgscan_learn_get_params(struct bgscan_learn_data *data,
				   const char *params)
{
	const char *pos;

	if (params == NULL)
		return 0;

	data->short_interval = atoi(params);

	pos = os_strchr(params, ':');
	if (pos == NULL)
		return 0;
	pos++;
	data->signal_threshold = atoi(pos);
	pos = os_strchr(pos, ':');
	if (pos == NULL) {
		wpa_printf(MSG_ERROR, "bgscan learn: Missing scan interval "
			   "for high signal");
		return -1;
	}
	pos++;
	data->long_interval = atoi(pos);
	pos = os_strchr(pos, ':');
	if (pos) {
		pos++;
		data->fname = os_strdup(pos);
	}

	return 0;
}


static int * bgscan_learn_get_supp_freqs(struct wpa_supplicant *wpa_s)
{
	struct hostapd_hw_modes *modes;
	int i, j, *freqs = NULL, *n;
	size_t count = 0;

	modes = wpa_s->hw.modes;
	if (modes == NULL)
		return NULL;

	for (i = 0; i < wpa_s->hw.num_modes; i++) {
		for (j = 0; j < modes[i].num_channels; j++) {
			if (modes[i].channels[j].flag & HOSTAPD_CHAN_DISABLED)
				continue;
			/* some hw modes (e.g. 11b & 11g) contain same freqs */
			if (in_array(freqs, modes[i].channels[j].freq))
				continue;
			n = os_realloc_array(freqs, count + 2, sizeof(int));
			if (n == NULL)
				continue;

			freqs = n;
			freqs[count] = modes[i].channels[j].freq;
			count++;
			freqs[count] = 0;
		}
	}

	return freqs;
}


static void * bgscan_learn_init(struct wpa_supplicant *wpa_s,
				const char *params,
				const struct wpa_ssid *ssid)
{
	struct bgscan_learn_data *data;

	data = os_zalloc(sizeof(*data));
	if (data == NULL)
		return NULL;
	dl_list_init(&data->bss);
	data->wpa_s = wpa_s;
	data->ssid = ssid;
	if (bgscan_learn_get_params(data, params) < 0) {
		os_free(data->fname);
		os_free(data);
		return NULL;
	}
	if (data->short_interval <= 0)
		data->short_interval = 30;
	if (data->long_interval <= 0)
		data->long_interval = 30;

	if (bgscan_learn_load(data) < 0) {
		os_free(data->fname);
		os_free(data);
		return NULL;
	}

	wpa_printf(MSG_DEBUG, "bgscan learn: Signal strength threshold %d  "
		   "Short bgscan interval %d  Long bgscan interval %d",
		   data->signal_threshold, data->short_interval,
		   data->long_interval);

	if (data->signal_threshold &&
	    wpa_drv_signal_monitor(wpa_s, data->signal_threshold, 4) < 0) {
		wpa_printf(MSG_ERROR, "bgscan learn: Failed to enable "
			   "signal strength monitoring");
	}

	data->supp_freqs = bgscan_learn_get_supp_freqs(wpa_s);
	data->scan_interval = data->short_interval;
	if (data->signal_threshold) {
		/* Poll for signal info to set initial scan interval */
		struct wpa_signal_info siginfo;
		if (wpa_drv_signal_poll(wpa_s, &siginfo) == 0 &&
		    siginfo.current_signal >= data->signal_threshold)
			data->scan_interval = data->long_interval;
	}

	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
			       data, NULL);

	/*
	 * This function is called immediately after an association, so it is
	 * reasonable to assume that a scan was completed recently. This makes
	 * us skip an immediate new scan in cases where the current signal
	 * level is below the bgscan threshold.
	 */
	os_get_reltime(&data->last_bgscan);

	return data;
}


static void bgscan_learn_deinit(void *priv)
{
	struct bgscan_learn_data *data = priv;
	struct bgscan_learn_bss *bss, *n;

	bgscan_learn_save(data);
	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	if (data->signal_threshold)
		wpa_drv_signal_monitor(data->wpa_s, 0, 0);
	os_free(data->fname);
	dl_list_for_each_safe(bss, n, &data->bss, struct bgscan_learn_bss,
			      list) {
		dl_list_del(&bss->list);
		bss_free(bss);
	}
	os_free(data->supp_freqs);
	os_free(data);
}


static int bgscan_learn_bss_match(struct bgscan_learn_data *data,
				  struct wpa_scan_res *bss)
{
	const u8 *ie;

	ie = wpa_scan_get_ie(bss, WLAN_EID_SSID);
	if (ie == NULL)
		return 0;

	if (data->ssid->ssid_len != ie[1] ||
	    os_memcmp(data->ssid->ssid, ie + 2, ie[1]) != 0)
		return 0; /* SSID mismatch */

	return 1;
}


static int bgscan_learn_notify_scan(void *priv,
				    struct wpa_scan_results *scan_res)
{
	struct bgscan_learn_data *data = priv;
	size_t i, j;
#define MAX_BSS 50
	u8 bssid[MAX_BSS * ETH_ALEN];
	size_t num_bssid = 0;

	wpa_printf(MSG_DEBUG, "bgscan learn: scan result notification");

	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
			       data, NULL);

	for (i = 0; i < scan_res->num; i++) {
		struct wpa_scan_res *res = scan_res->res[i];
		if (!bgscan_learn_bss_match(data, res))
			continue;

		if (num_bssid < MAX_BSS) {
			os_memcpy(bssid + num_bssid * ETH_ALEN, res->bssid,
				  ETH_ALEN);
			num_bssid++;
		}
	}
	wpa_printf(MSG_DEBUG, "bgscan learn: %u matching BSSes in scan "
		   "results", (unsigned int) num_bssid);

	for (i = 0; i < scan_res->num; i++) {
		struct wpa_scan_res *res = scan_res->res[i];
		struct bgscan_learn_bss *bss;

		if (!bgscan_learn_bss_match(data, res))
			continue;

		bss = bgscan_learn_get_bss(data, res->bssid);
		if (bss && bss->freq != res->freq) {
			wpa_printf(MSG_DEBUG, "bgscan learn: Update BSS "
			   MACSTR " freq %d -> %d",
				   MAC2STR(res->bssid), bss->freq, res->freq);
			bss->freq = res->freq;
		} else if (!bss) {
			wpa_printf(MSG_DEBUG, "bgscan learn: Add BSS " MACSTR
				   " freq=%d", MAC2STR(res->bssid), res->freq);
			bss = os_zalloc(sizeof(*bss));
			if (!bss)
				continue;
			os_memcpy(bss->bssid, res->bssid, ETH_ALEN);
			bss->freq = res->freq;
			dl_list_add(&data->bss, &bss->list);
		}

		for (j = 0; j < num_bssid; j++) {
			u8 *addr = bssid + j * ETH_ALEN;
			bgscan_learn_add_neighbor(bss, addr);
		}
	}

	/*
	 * A more advanced bgscan could process scan results internally, select
	 * the BSS and request roam if needed. This sample uses the existing
	 * BSS/ESS selection routine. Change this to return 1 if selection is
	 * done inside the bgscan module.
	 */

	return 0;
}


static void bgscan_learn_notify_beacon_loss(void *priv)
{
	wpa_printf(MSG_DEBUG, "bgscan learn: beacon loss");
	/* TODO: speed up background scanning */
}


static void bgscan_learn_notify_signal_change(void *priv, int above,
					      int current_signal,
					      int current_noise,
					      int current_txrate)
{
	struct bgscan_learn_data *data = priv;
	int scan = 0;
	struct os_reltime now;

	if (data->short_interval == data->long_interval ||
	    data->signal_threshold == 0)
		return;

	wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed "
		   "(above=%d current_signal=%d current_noise=%d "
		   "current_txrate=%d)", above, current_signal,
		   current_noise, current_txrate);
	if (data->scan_interval == data->long_interval && !above) {
		wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan "
			   "interval");
		data->scan_interval = data->short_interval;
		os_get_reltime(&now);
		if (now.sec > data->last_bgscan.sec + 1)
			scan = 1;
	} else if (data->scan_interval == data->short_interval && above) {
		wpa_printf(MSG_DEBUG, "bgscan learn: Start using long bgscan "
			   "interval");
		data->scan_interval = data->long_interval;
		eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
		eloop_register_timeout(data->scan_interval, 0,
				       bgscan_learn_timeout, data, NULL);
	} else if (!above) {
		/*
		 * Signal dropped further 4 dB. Request a new scan if we have
		 * not yet scanned in a while.
		 */
		os_get_reltime(&now);
		if (now.sec > data->last_bgscan.sec + 10)
			scan = 1;
	}

	if (scan) {
		wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan");
		eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
		eloop_register_timeout(0, 0, bgscan_learn_timeout, data, NULL);
	}
}


const struct bgscan_ops bgscan_learn_ops = {
	.name = "learn",
	.init = bgscan_learn_init,
	.deinit = bgscan_learn_deinit,
	.notify_scan = bgscan_learn_notify_scan,
	.notify_beacon_loss = bgscan_learn_notify_beacon_loss,
	.notify_signal_change = bgscan_learn_notify_signal_change,
};
Commit	Line	Data
c4d71c25 JM	1	/*
	2	* WPA Supplicant - background scan and roaming module: learn
	3	* Copyright (c) 2009-2010, Jouni Malinen <j@w1.fi>
	4	*
0f3d578e JM	5	* This software may be distributed under the terms of the BSD license.
0f3d578e JM	6	* See README for more details.
c4d71c25 JM	7	*/
	8
	9	#include "includes.h"
	10
	11	#include "common.h"
	12	#include "eloop.h"
fc480e88 JM	13	#include "list.h"
fc480e88 JM	14	#include "common/ieee802_11_defs.h"
c4d71c25 JM	15	#include "drivers/driver.h"
	16	#include "config_ssid.h"
	17	#include "wpa_supplicant_i.h"
	18	#include "driver_i.h"
	19	#include "scan.h"
	20	#include "bgscan.h"
	21
fc480e88 JM	22	struct bgscan_learn_bss {
	23	struct dl_list list;
	24	u8 bssid[ETH_ALEN];
	25	int freq;
3b7442e5 JM	26	u8 neigh; / num_neigh * ETH_ALEN buffer */
3b7442e5 JM	27	size_t num_neigh;
fc480e88 JM	28	};
fc480e88 JM	29
c4d71c25 JM	30	struct bgscan_learn_data {
	31	struct wpa_supplicant *wpa_s;
	32	const struct wpa_ssid *ssid;
	33	int scan_interval;
	34	int signal_threshold;
	35	int short_interval; /* use if signal < threshold */
	36	int long_interval; /* use if signal > threshold */
e72a001b	37	struct os_reltime last_bgscan;
2e8d6ae3	38	char *fname;
fc480e88	39	struct dl_list bss;
2e2a8d07 JM	40	int *supp_freqs;
2e2a8d07 JM	41	int probe_idx;
c4d71c25 JM	42	};
	43
	44
3b7442e5 JM	45	static void bss_free(struct bgscan_learn_bss *bss)
	46	{
	47	os_free(bss->neigh);
	48	os_free(bss);
	49	}
	50
	51
	52	static int bssid_in_array(u8 array, size_t array_len, const u8 bssid)
	53	{
	54	size_t i;
	55
	56	if (array == NULL \|\| array_len == 0)
	57	return 0;
	58
	59	for (i = 0; i < array_len; i++) {
	60	if (os_memcmp(array + i * ETH_ALEN, bssid, ETH_ALEN) == 0)
	61	return 1;
	62	}
	63
	64	return 0;
	65	}
	66
	67
	68	static void bgscan_learn_add_neighbor(struct bgscan_learn_bss *bss,
	69	const u8 *bssid)
	70	{
	71	u8 *n;
	72
	73	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	74	return;
	75	if (bssid_in_array(bss->neigh, bss->num_neigh, bssid))
	76	return;
	77
067ffa26	78	n = os_realloc_array(bss->neigh, bss->num_neigh + 1, ETH_ALEN);
3b7442e5 JM	79	if (n == NULL)
	80	return;
	81
	82	os_memcpy(n + bss->num_neigh * ETH_ALEN, bssid, ETH_ALEN);
	83	bss->neigh = n;
	84	bss->num_neigh++;
3b7442e5 JM	85	}
	86
	87
fc480e88 JM	88	static struct bgscan_learn_bss * bgscan_learn_get_bss(
	89	struct bgscan_learn_data data, const u8 bssid)
	90	{
	91	struct bgscan_learn_bss *bss;
	92
	93	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	94	if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
	95	return bss;
	96	}
	97	return NULL;
	98	}
	99
	100
2e8d6ae3 JM	101	static int bgscan_learn_load(struct bgscan_learn_data *data)
	102	{
	103	FILE *f;
	104	char buf[128];
3b7442e5	105	struct bgscan_learn_bss *bss;
2e8d6ae3 JM	106
	107	if (data->fname == NULL)
	108	return 0;
	109
	110	f = fopen(data->fname, "r");
	111	if (f == NULL)
	112	return 0;
	113
	114	wpa_printf(MSG_DEBUG, "bgscan learn: Loading data from %s",
	115	data->fname);
	116
	117	if (fgets(buf, sizeof(buf), f) == NULL \|\|
	118	os_strncmp(buf, "wpa_supplicant-bgscan-learn\n", 28) != 0) {
	119	wpa_printf(MSG_INFO, "bgscan learn: Invalid data file %s",
	120	data->fname);
	121	fclose(f);
	122	return -1;
	123	}
	124
fc480e88 JM	125	while (fgets(buf, sizeof(buf), f)) {
fc480e88 JM	126	if (os_strncmp(buf, "BSS ", 4) == 0) {
fc480e88 JM	127	bss = os_zalloc(sizeof(*bss));
	128	if (!bss)
	129	continue;
	130	if (hwaddr_aton(buf + 4, bss->bssid) < 0) {
3b7442e5	131	bss_free(bss);
fc480e88 JM	132	continue;
	133	}
	134	bss->freq = atoi(buf + 4 + 18);
	135	dl_list_add(&data->bss, &bss->list);
	136	wpa_printf(MSG_DEBUG, "bgscan learn: Loaded BSS "
	137	"entry: " MACSTR " freq=%d",
	138	MAC2STR(bss->bssid), bss->freq);
	139	}
3b7442e5 JM	140
	141	if (os_strncmp(buf, "NEIGHBOR ", 9) == 0) {
	142	u8 addr[ETH_ALEN];
	143
	144	if (hwaddr_aton(buf + 9, addr) < 0)
	145	continue;
	146	bss = bgscan_learn_get_bss(data, addr);
	147	if (bss == NULL)
	148	continue;
	149	if (hwaddr_aton(buf + 9 + 18, addr) < 0)
	150	continue;
	151
	152	bgscan_learn_add_neighbor(bss, addr);
	153	}
fc480e88 JM	154	}
fc480e88 JM	155
2e8d6ae3 JM	156	fclose(f);
	157	return 0;
	158	}
	159
	160
	161	static void bgscan_learn_save(struct bgscan_learn_data *data)
	162	{
	163	FILE *f;
fc480e88	164	struct bgscan_learn_bss *bss;
2e8d6ae3 JM	165
	166	if (data->fname == NULL)
	167	return;
	168
	169	wpa_printf(MSG_DEBUG, "bgscan learn: Saving data to %s",
	170	data->fname);
	171
	172	f = fopen(data->fname, "w");
	173	if (f == NULL)
	174	return;
	175	fprintf(f, "wpa_supplicant-bgscan-learn\n");
	176
fc480e88 JM	177	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	178	fprintf(f, "BSS " MACSTR " %d\n",
	179	MAC2STR(bss->bssid), bss->freq);
	180	}
	181
3b7442e5 JM	182	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	183	size_t i;
	184	for (i = 0; i < bss->num_neigh; i++) {
	185	fprintf(f, "NEIGHBOR " MACSTR " " MACSTR "\n",
	186	MAC2STR(bss->bssid),
	187	MAC2STR(bss->neigh + i * ETH_ALEN));
	188	}
	189	}
	190
2e8d6ae3 JM	191	fclose(f);
	192	}
	193
	194
fc480e88 JM	195	static int in_array(int *array, int val)
	196	{
	197	int i;
	198
	199	if (array == NULL)
	200	return 0;
	201
	202	for (i = 0; array[i]; i++) {
	203	if (array[i] == val)
	204	return 1;
	205	}
	206
	207	return 0;
	208	}
	209
	210
	211	static int * bgscan_learn_get_freqs(struct bgscan_learn_data *data,
	212	size_t *count)
	213	{
	214	struct bgscan_learn_bss *bss;
	215	int freqs = NULL, n;
	216
	217	*count = 0;
	218
	219	dl_list_for_each(bss, &data->bss, struct bgscan_learn_bss, list) {
	220	if (in_array(freqs, bss->freq))
	221	continue;
067ffa26	222	n = os_realloc_array(freqs, *count + 2, sizeof(int));
fc480e88 JM	223	if (n == NULL)
	224	return freqs;
	225	freqs = n;
	226	freqs[*count] = bss->freq;
	227	(*count)++;
	228	freqs[*count] = 0;
	229	}
	230
	231	return freqs;
	232	}
	233
	234
2e2a8d07 JM	235	static int * bgscan_learn_get_probe_freq(struct bgscan_learn_data *data,
	236	int *freqs, size_t count)
	237	{
	238	int idx, *n;
	239
	240	if (data->supp_freqs == NULL)
	241	return freqs;
	242
3e06180f EP	243	idx = data->probe_idx;
3e06180f EP	244	do {
2e2a8d07 JM	245	if (!in_array(freqs, data->supp_freqs[idx])) {
	246	wpa_printf(MSG_DEBUG, "bgscan learn: Probe new freq "
	247	"%u", data->supp_freqs[idx]);
3e06180f EP	248	data->probe_idx = idx + 1;
	249	if (data->supp_freqs[data->probe_idx] == 0)
	250	data->probe_idx = 0;
067ffa26	251	n = os_realloc_array(freqs, count + 2, sizeof(int));
2e2a8d07 JM	252	if (n == NULL)
	253	return freqs;
	254	freqs = n;
	255	freqs[count] = data->supp_freqs[idx];
	256	count++;
	257	freqs[count] = 0;
	258	break;
	259	}
	260
	261	idx++;
3e06180f EP	262	if (data->supp_freqs[idx] == 0)
	263	idx = 0;
	264	} while (idx != data->probe_idx);
2e2a8d07 JM	265
	266	return freqs;
	267	}
	268
	269
c4d71c25 JM	270	static void bgscan_learn_timeout(void eloop_ctx, void timeout_ctx)
	271	{
	272	struct bgscan_learn_data *data = eloop_ctx;
	273	struct wpa_supplicant *wpa_s = data->wpa_s;
	274	struct wpa_driver_scan_params params;
fc480e88	275	int *freqs = NULL;
2e2a8d07 JM	276	size_t count, i;
2e2a8d07 JM	277	char msg[100], *pos;
c4d71c25 JM	278
	279	os_memset(&params, 0, sizeof(params));
	280	params.num_ssids = 1;
	281	params.ssids[0].ssid = data->ssid->ssid;
	282	params.ssids[0].ssid_len = data->ssid->ssid_len;
fc480e88 JM	283	if (data->ssid->scan_freq)
	284	params.freqs = data->ssid->scan_freq;
	285	else {
	286	freqs = bgscan_learn_get_freqs(data, &count);
	287	wpa_printf(MSG_DEBUG, "bgscan learn: BSSes in this ESS have "
	288	"been seen on %u channels", (unsigned int) count);
2e2a8d07 JM	289	freqs = bgscan_learn_get_probe_freq(data, freqs, count);
	290
	291	msg[0] = '\0';
	292	pos = msg;
	293	for (i = 0; freqs && freqs[i]; i++) {
	294	int ret;
	295	ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d",
	296	freqs[i]);
d85e1fc8	297	if (os_snprintf_error(msg + sizeof(msg) - pos, ret))
2e2a8d07 JM	298	break;
	299	pos += ret;
	300	}
	301	pos[0] = '\0';
	302	wpa_printf(MSG_DEBUG, "bgscan learn: Scanning frequencies:%s",
	303	msg);
fc480e88 JM	304	params.freqs = freqs;
fc480e88 JM	305	}
c4d71c25 JM	306
	307	wpa_printf(MSG_DEBUG, "bgscan learn: Request a background scan");
	308	if (wpa_supplicant_trigger_scan(wpa_s, &params)) {
	309	wpa_printf(MSG_DEBUG, "bgscan learn: Failed to trigger scan");
	310	eloop_register_timeout(data->scan_interval, 0,
	311	bgscan_learn_timeout, data, NULL);
	312	} else
e72a001b	313	os_get_reltime(&data->last_bgscan);
fc480e88	314	os_free(freqs);
c4d71c25 JM	315	}
	316
	317
	318	static int bgscan_learn_get_params(struct bgscan_learn_data *data,
	319	const char *params)
	320	{
	321	const char *pos;
	322
	323	if (params == NULL)
	324	return 0;
	325
	326	data->short_interval = atoi(params);
	327
	328	pos = os_strchr(params, ':');
	329	if (pos == NULL)
	330	return 0;
	331	pos++;
	332	data->signal_threshold = atoi(pos);
	333	pos = os_strchr(pos, ':');
	334	if (pos == NULL) {
	335	wpa_printf(MSG_ERROR, "bgscan learn: Missing scan interval "
	336	"for high signal");
	337	return -1;
	338	}
	339	pos++;
	340	data->long_interval = atoi(pos);
2e8d6ae3 JM	341	pos = os_strchr(pos, ':');
	342	if (pos) {
	343	pos++;
	344	data->fname = os_strdup(pos);
	345	}
c4d71c25 JM	346
	347	return 0;
	348	}
	349
	350
2e2a8d07 JM	351	static int * bgscan_learn_get_supp_freqs(struct wpa_supplicant *wpa_s)
	352	{
	353	struct hostapd_hw_modes *modes;
2e2a8d07 JM	354	int i, j, freqs = NULL, n;
	355	size_t count = 0;
	356
6bf731e8 CL	357	modes = wpa_s->hw.modes;
6bf731e8 CL	358	if (modes == NULL)
2e2a8d07 JM	359	return NULL;
2e2a8d07 JM	360
6bf731e8	361	for (i = 0; i < wpa_s->hw.num_modes; i++) {
2e2a8d07 JM	362	for (j = 0; j < modes[i].num_channels; j++) {
	363	if (modes[i].channels[j].flag & HOSTAPD_CHAN_DISABLED)
	364	continue;
7dab1193 EP	365	/* some hw modes (e.g. 11b & 11g) contain same freqs */
	366	if (in_array(freqs, modes[i].channels[j].freq))
	367	continue;
067ffa26	368	n = os_realloc_array(freqs, count + 2, sizeof(int));
6bf731e8	369	if (n == NULL)
2e2a8d07 JM	370	continue;
	371
	372	freqs = n;
	373	freqs[count] = modes[i].channels[j].freq;
	374	count++;
	375	freqs[count] = 0;
	376	}
2e2a8d07	377	}
2e2a8d07 JM	378
	379	return freqs;
	380	}
	381
	382
c4d71c25 JM	383	static void * bgscan_learn_init(struct wpa_supplicant *wpa_s,
	384	const char *params,
	385	const struct wpa_ssid *ssid)
	386	{
	387	struct bgscan_learn_data *data;
	388
	389	data = os_zalloc(sizeof(*data));
	390	if (data == NULL)
	391	return NULL;
fc480e88	392	dl_list_init(&data->bss);
c4d71c25 JM	393	data->wpa_s = wpa_s;
	394	data->ssid = ssid;
	395	if (bgscan_learn_get_params(data, params) < 0) {
2e8d6ae3	396	os_free(data->fname);
c4d71c25 JM	397	os_free(data);
	398	return NULL;
	399	}
	400	if (data->short_interval <= 0)
	401	data->short_interval = 30;
	402	if (data->long_interval <= 0)
	403	data->long_interval = 30;
	404
2e8d6ae3 JM	405	if (bgscan_learn_load(data) < 0) {
	406	os_free(data->fname);
	407	os_free(data);
	408	return NULL;
	409	}
	410
c4d71c25 JM	411	wpa_printf(MSG_DEBUG, "bgscan learn: Signal strength threshold %d "
	412	"Short bgscan interval %d Long bgscan interval %d",
	413	data->signal_threshold, data->short_interval,
	414	data->long_interval);
	415
	416	if (data->signal_threshold &&
	417	wpa_drv_signal_monitor(wpa_s, data->signal_threshold, 4) < 0) {
	418	wpa_printf(MSG_ERROR, "bgscan learn: Failed to enable "
	419	"signal strength monitoring");
	420	}
	421
2e2a8d07	422	data->supp_freqs = bgscan_learn_get_supp_freqs(wpa_s);
c4d71c25	423	data->scan_interval = data->short_interval;
f4c73ae6 ES	424	if (data->signal_threshold) {
	425	/* Poll for signal info to set initial scan interval */
	426	struct wpa_signal_info siginfo;
	427	if (wpa_drv_signal_poll(wpa_s, &siginfo) == 0 &&
	428	siginfo.current_signal >= data->signal_threshold)
	429	data->scan_interval = data->long_interval;
	430	}
	431
c4d71c25 JM	432	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
c4d71c25 JM	433	data, NULL);
9ff80a10 JM	434
	435	/*
	436	* This function is called immediately after an association, so it is
	437	* reasonable to assume that a scan was completed recently. This makes
	438	* us skip an immediate new scan in cases where the current signal
	439	* level is below the bgscan threshold.
	440	*/
e72a001b	441	os_get_reltime(&data->last_bgscan);
9ff80a10	442
c4d71c25 JM	443	return data;
	444	}
	445
	446
	447	static void bgscan_learn_deinit(void *priv)
	448	{
	449	struct bgscan_learn_data *data = priv;
fc480e88 JM	450	struct bgscan_learn_bss bss, n;
fc480e88 JM	451
2e8d6ae3	452	bgscan_learn_save(data);
c4d71c25 JM	453	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	454	if (data->signal_threshold)
	455	wpa_drv_signal_monitor(data->wpa_s, 0, 0);
2e8d6ae3	456	os_free(data->fname);
fc480e88 JM	457	dl_list_for_each_safe(bss, n, &data->bss, struct bgscan_learn_bss,
	458	list) {
	459	dl_list_del(&bss->list);
3b7442e5	460	bss_free(bss);
fc480e88	461	}
2e2a8d07	462	os_free(data->supp_freqs);
c4d71c25 JM	463	os_free(data);
	464	}
	465
	466
fc480e88 JM	467	static int bgscan_learn_bss_match(struct bgscan_learn_data *data,
	468	struct wpa_scan_res *bss)
	469	{
	470	const u8 *ie;
	471
	472	ie = wpa_scan_get_ie(bss, WLAN_EID_SSID);
	473	if (ie == NULL)
	474	return 0;
	475
	476	if (data->ssid->ssid_len != ie[1] \|\|
	477	os_memcmp(data->ssid->ssid, ie + 2, ie[1]) != 0)
	478	return 0; /* SSID mismatch */
	479
	480	return 1;
	481	}
	482
	483
c4d71c25 JM	484	static int bgscan_learn_notify_scan(void *priv,
	485	struct wpa_scan_results *scan_res)
	486	{
	487	struct bgscan_learn_data *data = priv;
3b7442e5 JM	488	size_t i, j;
	489	#define MAX_BSS 50
	490	u8 bssid[MAX_BSS * ETH_ALEN];
	491	size_t num_bssid = 0;
c4d71c25 JM	492
	493	wpa_printf(MSG_DEBUG, "bgscan learn: scan result notification");
	494
	495	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	496	eloop_register_timeout(data->scan_interval, 0, bgscan_learn_timeout,
	497	data, NULL);
	498
3b7442e5 JM	499	for (i = 0; i < scan_res->num; i++) {
	500	struct wpa_scan_res *res = scan_res->res[i];
	501	if (!bgscan_learn_bss_match(data, res))
	502	continue;
	503
	504	if (num_bssid < MAX_BSS) {
	505	os_memcpy(bssid + num_bssid * ETH_ALEN, res->bssid,
	506	ETH_ALEN);
	507	num_bssid++;
	508	}
	509	}
	510	wpa_printf(MSG_DEBUG, "bgscan learn: %u matching BSSes in scan "
	511	"results", (unsigned int) num_bssid);
	512
fc480e88 JM	513	for (i = 0; i < scan_res->num; i++) {
	514	struct wpa_scan_res *res = scan_res->res[i];
	515	struct bgscan_learn_bss *bss;
	516
	517	if (!bgscan_learn_bss_match(data, res))
	518	continue;
3b7442e5	519
fc480e88 JM	520	bss = bgscan_learn_get_bss(data, res->bssid);
	521	if (bss && bss->freq != res->freq) {
	522	wpa_printf(MSG_DEBUG, "bgscan learn: Update BSS "
	523	MACSTR " freq %d -> %d",
	524	MAC2STR(res->bssid), bss->freq, res->freq);
	525	bss->freq = res->freq;
	526	} else if (!bss) {
	527	wpa_printf(MSG_DEBUG, "bgscan learn: Add BSS " MACSTR
	528	" freq=%d", MAC2STR(res->bssid), res->freq);
	529	bss = os_zalloc(sizeof(*bss));
	530	if (!bss)
	531	continue;
	532	os_memcpy(bss->bssid, res->bssid, ETH_ALEN);
	533	bss->freq = res->freq;
	534	dl_list_add(&data->bss, &bss->list);
	535	}
3b7442e5 JM	536
	537	for (j = 0; j < num_bssid; j++) {
	538	u8 addr = bssid + j ETH_ALEN;
	539	bgscan_learn_add_neighbor(bss, addr);
	540	}
fc480e88 JM	541	}
fc480e88 JM	542
c4d71c25 JM	543	/*
	544	* A more advanced bgscan could process scan results internally, select
	545	* the BSS and request roam if needed. This sample uses the existing
	546	* BSS/ESS selection routine. Change this to return 1 if selection is
	547	* done inside the bgscan module.
	548	*/
	549
	550	return 0;
	551	}
	552
	553
	554	static void bgscan_learn_notify_beacon_loss(void *priv)
	555	{
	556	wpa_printf(MSG_DEBUG, "bgscan learn: beacon loss");
	557	/* TODO: speed up background scanning */
	558	}
	559
	560
60a972a6	561	static void bgscan_learn_notify_signal_change(void *priv, int above,
174fa789 PS	562	int current_signal,
	563	int current_noise,
	564	int current_txrate)
c4d71c25 JM	565	{
c4d71c25 JM	566	struct bgscan_learn_data *data = priv;
266c828e	567	int scan = 0;
e72a001b	568	struct os_reltime now;
c4d71c25 JM	569
	570	if (data->short_interval == data->long_interval \|\|
	571	data->signal_threshold == 0)
	572	return;
	573
	574	wpa_printf(MSG_DEBUG, "bgscan learn: signal level changed "
174fa789 PS	575	"(above=%d current_signal=%d current_noise=%d "
	576	"current_txrate=%d)", above, current_signal,
	577	current_noise, current_txrate);
c4d71c25	578	if (data->scan_interval == data->long_interval && !above) {
9ff80a10 JM	579	wpa_printf(MSG_DEBUG, "bgscan learn: Start using short bgscan "
9ff80a10 JM	580	"interval");
c4d71c25	581	data->scan_interval = data->short_interval;
e72a001b	582	os_get_reltime(&now);
9ff80a10 JM	583	if (now.sec > data->last_bgscan.sec + 1)
9ff80a10 JM	584	scan = 1;
c4d71c25 JM	585	} else if (data->scan_interval == data->short_interval && above) {
	586	wpa_printf(MSG_DEBUG, "bgscan learn: Start using long bgscan "
	587	"interval");
	588	data->scan_interval = data->long_interval;
	589	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	590	eloop_register_timeout(data->scan_interval, 0,
	591	bgscan_learn_timeout, data, NULL);
	592	} else if (!above) {
c4d71c25 JM	593	/*
	594	* Signal dropped further 4 dB. Request a new scan if we have
	595	* not yet scanned in a while.
	596	*/
e72a001b	597	os_get_reltime(&now);
9ff80a10 JM	598	if (now.sec > data->last_bgscan.sec + 10)
	599	scan = 1;
	600	}
	601
	602	if (scan) {
	603	wpa_printf(MSG_DEBUG, "bgscan learn: Trigger immediate scan");
	604	eloop_cancel_timeout(bgscan_learn_timeout, data, NULL);
	605	eloop_register_timeout(0, 0, bgscan_learn_timeout, data, NULL);
c4d71c25 JM	606	}
	607	}
	608
	609
	610	const struct bgscan_ops bgscan_learn_ops = {
	611	.name = "learn",
	612	.init = bgscan_learn_init,
	613	.deinit = bgscan_learn_deinit,
	614	.notify_scan = bgscan_learn_notify_scan,
	615	.notify_beacon_loss = bgscan_learn_notify_beacon_loss,
	616	.notify_signal_change = bgscan_learn_notify_signal_change,
	617	};